1. Field of the Invention
The present invention relates to a wide zoom lens system suitable for a still camera and a digital camera.
2. Related Background Art
A so-called digital still camera using a solid-state imaging device such as a CCD has recently gained in popularity in place of a film camera. Accordingly, zoom lens systems having a zoom ratio of about three suitable for a solid-state imaging device have been proposed in Japanese Patent Application Laid-Open Nos. 11-23967, 2003-107348, and 2003-107352.
However, the zoom lens system proposed in Japanese Patent Application Laid-Open No. 11-23967 has an angle of view in the wide-angle end state of about 60 degrees, so that it has not met expectations to have a wider angle of view.
In order to solve this, the zoom lens systems proposed in Japanese Patent Application Laid-Open Nos. 2003-107348, and 2003-107352 have been known. However, they have an angle of view in the wide-angle end state of about 80 degrees and f-number in the wide-angle end state of about 2.7, so that they have not been sufficient in both ways of a wide angle of view and a high speed aperture ratio.